Monday, April 24, 2006

Madeleine the Robot Turtle

Tom Simonite

A robotic turtle could help engineers build better autonomous underwater vehicles and answer fundamental questions about how prehistoric beasts swam. The robot, called Madeleine, is already helping researchers understand when it is best to swim with four flippers and when to use two.

Madeleine is similar in size and weight to a Kemp's Ridley or Olive Ridley sea turtle, measuring 80 centimetres by 30 cm and weighing 24 kilograms. The robot also has a comparable power output, between 5 and 10 watts per kilogram, depending on how hard it is working.

By imitating the design of a turtle, the researchers hope to build more efficient ocean robots, with flippers. "The thinking is that if nature did it, it must be good," explains John Long, one of Madeleine's makers from Vassar College, in New York, US

Long and colleagues used their robo-turtle and a swimming pool to experiment with different forms of flipper propulsion. They showed that four flippers are best for acceleration and stopping, while two flippers are more efficient for simply cruising along.